1. Industrial Useful Field
This invention relates to a clutch cover assembly for use in a diaphragm spring type friction clutch suitable for an automobile and similar vehicles.
2. Prior Art
Generally, in this type of a clutch a pair of wire rings are provided on both sides of a diaphragm spring for urging a pressure plate into contact with a clutch disk. The wire rings form a supporting point for the diaphragm spring. Further, a structure is widely used, in which the wire rings are supported by tabs provided at an inner periphery of a clutch cover.
However, because the tabs are extended through openings (expanded portions of radial slits) of the diaphragm spring to a pressure plate side, circumferential clearances are produced between tab side edges and spring circumferential end faces of the openings. Therefore, it is inevitable in a conventional clutch that the diaphragm spring rotates relatively to the clutch cover and the following disadvantages arise.
Namely, the clutch cover rotates together with an engine flywheel and, generally, the diaphragm spring also rotates together with the clutch cover. Because a release bearing obstructs or restrains the rotation of the diaphragm spring, in the event when a seizure is produced between an inner peripheral part of the diaphragm spring and the release bearing, the diaphragm spring rotates relatively to the clutch cover by a length corresponding to the clearance and the tab side edge collides against the opening end face of the diaphragm spring. Consequently, the diaphragm spring moves out of position and cuts into the tab. The diaphragm spring does not functioning smoothly and the releasing efficiency of the clutch fluctuates. The specified clutch operation characteristic is not obtainable. Further, in an extreme case, an early breakage of the diaphragm spring is induced.